1. Field of the Invention
This invention relates to a solar powered lamp, particularly to a solar powered lamp having a cold-cathode fluorescent bulb, and more particularly to a solar powered lamp with a cold-cathode fluorescent bulb and an auxiliary startup device.
2. Description of the Related Art
Solar powered lamp has been commonly used in place of the electrically powered lamp to illuminate pathways, yards, parks and other areas, for the purpose of saving existing fuel resources and protecting the environment from pollution.
U.S. Pat. No. 5,155,668 entitled “Solar Power Lamp Utilizing Cold Cathode Fluorescent Illuminating and Method of Facilitating Same” discloses a solar powered lamp, which utilizes photovoltaic devices to charge batteries which can activate a light source formed by the CCFL, in the absence of sunlight.
Conventionally, in a device for driving a cold-cathode fluorescent lamp (CCFL), as disclosed in the '668 patent, a direct-current voltage is needed to be converted into a high-tension alternating voltage by a “direct-current voltage/alternating voltage” inverter circuit (hereinafter referred to as a DC/AC inverter circuit). Then the resulting high-tension alternating voltage is supplied to the cold-cathode fluorescent lamp to light it.
In the cold-cathode fluorescent lamp, the value of the alternating voltage which is required to drive the lamp is about two or three times of the voltage which is required to light the lamp. Therefore, if the DC/AC inverter circuit converts, for example, a DC voltage of 4 volts directly to AC voltage of 1800 volts, and the CCFL operates at about 400 volts, the efficiency of the voltaic-photo transformation will be decreased significantly.